170421: He committed zina with his daughter so his sons threw him out and disowned him

What will be the punishment applicable on that person who did zina with her daughter while his wife is alive?
due to zina with his daughter,his sons threw away from the home and not sponsoring his father any more...is the act of sons threwing away their father due to commiting zina is right or not?
please give fatwa on above staatements.

Praise be to Allaah.

Undoubtedly this is a revolting and abhorrent action that is
unacceptable to sound human nature and decent souls, let alone the soul of
the people of Islam and faith who regard zina with a woman who is not a
relative as abhorrent, so how about if it is with one who is a mahram? How
about with the man’s daughter who came from his loins?

By Allah, the calamity that has befallen his sons is a great
calamity and we ask Allah to help them and to grant the Muslims well-being.

Despite what this father has fallen into of degenerate
behaviour, he still has a father’s right to kind treatment and upholding
ties of kinship, whilst also fulfilling the duty to Allah, may He be
exalted, of offering advice, denouncing the evil and preventing that from
happening again in the future.

If the sons advise him and he shows signs of repentance and
regret, or his being thrown out of the house has the effect of causing him
to repent and regret what he did, then the sons have to honour him and pay
attention to his rights, whilst taking precautions with regard to the
daughter’s (or daughters’) interactions with him. They should not be
careless about uncovering in front of him, and he should not be allowed to
be alone with one of them. The sons should also bear in mind that sin is
always possible for the son of Adam, but no matter how great the sin, if the
person repents from it and mends his ways, Allah will accept his
repentance.

But if he gives no sign of having repented and regretted it,
and there is the fear that if he stays in the house he will continue to be
tempted, then the sons have to give him accommodation in a separate house,
and they should treat him with kindness as is required of them, or the
daughter should go and live with one of her trustworthy mahrams, whilst the
father stays in his house. That is so as to ward off his evil, whilst still
giving him his rights.